The present invention relates to a molded product of activated carbon and a method for production thereof.
A molded product of activated carbon of the present invention is excellent in an adsorptive capability and mechanical strength and it can be used in a wide range of fields for removal of malodor evolved in wastewater treatment facilities, solvent recovery, ozone treatment and the like.
So far some production methods for molded product of activated carbon using phenol-aldehyde type resin as a binder have been known. Japanese Unexamined Patent Publication No. 115110/1974 discloses a method for producing a molded product of activated carbon by adding a phenol-aldehyde type resin to a carbon material such as charcoal or the like, molding the resulted mixture with an extruder, and then carbonizing the molding, optionally activating the molding after the carbonization. However, the specific surface area of the activated carbon after carbonization is no more than 300 m2/g and the activation should be carried out to obtain a molded product with the specific surface area of 1,100 m2/g. Japanese Unexamined Patent Publication No.27130/1982 and Japanese Unexamined Patent Publication No. 42039/1991 disclose methods wherein a synthetic resin fiber of a phenol type resin, a melamine type resin and the like are used as a carbonaceous material and a powdered activated carbon is used as a carbon material, respectively, and after the respective carbon materials are mixed with a phenol resin type binder and molded, and the resulting molded products are carbonized and activated.
However, after molding the above methods require the activation step of the carbon material and consequently, the production cost is high and the molded products are poor in the mechanical strength. Therefore, these methods are not preferable from the industrial point of view.
Japanese Unexamined Patent Publication No. 167118/1980 and Japanese Unexamined Patent Publication No. 207119/1995 disclose methods for producing a molded product of activated carbon by molding an activated carbon using a phenol-aldehyde type resin as a binder in liquid state at a normal temperature, drying and curing the obtained molding. However, in the case of these techniques, no activation is carried out and the phenol-aldehyde type resin as a binder blocks up the pores of the activated carbon, so that it results in a problem that the adsorption capability of the activated carbon is considerably lowered.
Problems To Be Solved by the Invention
In conventional methods as described above, there are problems that a step of activation after carbonization is indispensable in order to obtain the activated carbon moldings having a high adsorption capability even when an activated carbon and a phenol-aldehyde type resin are used as raw materials, and that the production process becomes complicated and the mechanical strength of the moldings is poor.
Especially, when the structure of a molded product of activated carbon is honeycomb, a high mechanical strength is required as well as the high adsorption capability. An activated carbon honeycomb available in the market is generally produced by adding a binder such as methylcellulose or the like together with an inorganic material such as clay to an activated carbon, kneading and molding the obtained mixture, and then carbonizing the molding. However, the activated carbon honeycombs produced by the above methods have problems that the mechanical strength is considerably decreased if it is used under the conditions where it is contacted with an acid such as in the case of using it for deodorization in wastewater treatment facilities
Means for Solving the Problems
The present invention provides a molded product of activated carbon with a high adsorption capability and a high mechanical strength and a method for producing the molded product of activated carbon by molding a kneaded mixture containing an activated carbon, a solvent, and a phenol-aldehyde type resin being solid in a normal temperature (25xc2x0 C.) and containing 50 to 95% by weight of components soluble in the solvent, drying and curing the molding, and then carbonizing the molding in the inert gas atmosphere without activation step to follow.
That is, the invention provides:
(1.) A molded product of activated carbon obtained by the steps comprising (1) molding a kneaded mixture containing an activated carbon, a solvent, and a phenol-aldehyde type resin being solid in a normal temperature and containing 50 to 95% by weight of components soluble in the solvent, (2) drying and curing the molding, and then (3) carbonizing the molding in an inert gas atmosphere:
(2.) The molded product of activated carbon as described in (1.) in which the amount of the phenol-aldehyde type resin is 10 to 80% by weight relative to the total weight of the activated carbon and the phenol-aldehyde type resin and the amount of the solvent is 10 to 60% by weight relative to the total weight of the activated carbon and phenol-aldehyde type resin:
(3.) The molded product of activated carbon as described in (1.) in which the shape of the molding is a pellet shape, a spherical shape, or a honeycomb shape:
(4.) The molded product of activated carbon as described in (1.) in which the solvent is alcohols, ethers, ketones, esters, aprotic solvent, or a mixture of water with at least one of these solvents:
(5.) The molded product of activated carbon as described in (1.) in which the drying is carried out at 70 to 150xc2x0 C.:
(6.) The molded product of activated carbon as described in (1.) in which the carbonization is carried out at 500 to 1500xc2x0 C.: and
(7.) A method of producing a molded product of activated carbon comprising steps of (1) molding a kneaded mixture containing an activated carbon, a solvent, and a phenol-aldehyde type resin being solid in a normal temperature and containing 50 to 95% by weight of components soluble in the solvent, (2) drying and curing the molding, and then (3) carbonizing the molding in the inert gas atmosphere: